Our new '03 3.7 ram is throwing the code P0455 which is the Evaporative emissions system or something like that. Also, I used the search but didn't find any specific info for this vehicle. Anyway I realize that it is a leak somewhere in the system but I am not certain where to look. I checked the gas cap and it seems fine so I want to move onto checking the lines. I don't have a repair manual for this truck yet so I am kinda searching blind. Thanks for any tips everyone.

 

well...just replace gas cap. it will prolly fix it.

 

Rather than waste money on the cap that MIGHT be bad, id rather check the other possibilities first. I'll check what I can today.

 

My truck has the same code and the gas cap did nothing. The mechanic told me to check the charcoal canister and all of the lines leading in and out of it. Look for the littlest crack and there is your leak. The canister should be under the drivers side of the truck. I'll let you know where I find mine at.

 

Thanks. I will check out the canister tonight.

 

they may have a gas cap tester at your local auto parts store...not to buy, but to use right there in front of them. Call around. I've worked on similar evap problems on tons of vehicles. It WASN'T the gas cap only once, and it was in the lines right under the gas tank nozzle under the car.

and whatever, a gas cap is like $10 bucks. Get one that's lightweight, so that if it doesn't fix the problem, you can call it a weigh reducing mod =)

 

Good advice but you can make mine your second. I replaced the cap and code came back after resetting the computer. Also I am just saying what my dodge mechanic told me when I brought it in for the code.

Either way it is one of the two just get under there with a flashlight and start looking for those cracked lines

 

If the cap is cheap I'll go ahead and replace it. It doesn't tighten very well but my mustang doesn't either, so I assumed it was fine.

 

BRO! https://dodgeforum.com/forum/v6-spec...-my-truck.html I had the exact same problem. Here is the post.

 

Yes, I saw your thread. I'm going to go ahead and replace the gas cap with a locking one, since I think it's a good investment for when the gas prices get high again. I hope that's the problem but I want to say that I could hear some leaking air in the engine bay with the engine running. It's hard to to tell for sure, but it sounded like it was coming from the power steering fluid reservoir area. If the cap fixes the problem I won't worry about it.